Scale corrector



SCALE GORRECTOR Original Filed Oct. 20

6 Sheets-Sheet l I CORRECTOR I I SCALE I: MODULATOR i lllll m a j N 9 Ro T (/N m m w m M a W W 9 2 a v III l l I J w 3 3U. .ml .1 j R llll E m3 LC A w a \m n w m F I IL T 5 W I I l I I 2 llllllll l|.

INVENTORS. John P. Woods Edwin E Neifzel,

Torn Prickeff Jr. W {M ATTEST.

ATTORNEY.

Oct. 3, 1967 J. P. WOODS ETAL SCALE CORRECTOR Original Filed Oct. 20,1960 6 Sheets-Sheet 2 +270 1 VOLTS J 5 I E25 I g l r To HEAD 7 39K l 51I L06 3 I RECORD 5E5 l I REcoRo 558% I I g MARKER L I 2 MODULATOR l x vx N $87 LOG N o? i Q g RECORD Q|| l @a 1 HF 80 TO MARKER 5? HEAD 23 fi450v fir TO POWER SUPPLYO Fig. 2

ATTEST.

INVENTORS. John P. Woods. .Edwin B. Neirzel. Torn Prickerf Jr.

6644 ATTORNEY.

Oct 3, 1967 J. P. WOODS ETAL 3,345,499

SCALE CORRECTOR 6 Sheets-Sheet 5 Original Filed Oct. 20

ESE n n 5&8 a a 3 BE mmaom 5 33mm 3? zmdw m mm 20 -65: I IMP 5Q fi am I1 mm l 5 v m O u 5201 h M. W H mm x 39 I 153. Kim mm 52E wmia com mm On;2...: 00m

- INVENTORSL John P. Woods.

ATTEST.

Edwin E. Neifzel. Tom Prickeff Jr.

ATTORNEY. v

@ci. 3, 1967 J. P. WOODS ETAL 3,345,499

SCALE GORRECTOR Original Filed Oct. 2-0. 1960 6 Sheets-Sheet 4 5.9xzotsw ATTORNEY.

ct. 3, 1%? J. P. WOODS ETAL- 3,345,499

SCALE CORRECTOR Original Filed Oct. 20, 1960 6 Sheets-Sheet 5 MODULATOR4 7 MODULATOR Fig. 5.

INVENTORS. John F? Woods. ATTEST- Edwin B. Neifzel.

Z z Tom Prickeff Jn MXXM ATTORNEY.

6 Sheets-Sheet 6 J. P. WOODS ETAL SCA-LE-C'ORRECTOR Oct. 3, 1967Original Filed Oct. 20

102 58: 9 5. mm I I I I l l I 7|! III 55mm 53mm no. $23002 K m9 Y M k nM m U wzmww m 3o 5%: rll mwlffim ll|llmfllllllL INVENTORS John P Woods.Edwin E Neifzel. Tom Prickelf Jr.

ATTORNE Y.

ATTEST United States Patent ABSTRACT OF THE DISCLOSURE A method andrecord and scale changing device for transferring a function from afirst record medium to a second record medium wherein the scale of thefunction is changed. Subcomponents include a scale corrector and a90-degree phase shifting circuit. A predetermined code which dictatesthe scale changes is placed on the first record medium. The function andcode are translated into electrical signals which modulate a carrier.The scale of the function is changed as the electrical signalsrepresenting the function are recorded on the second medium by varyingthe speed of one of the mediums or advancing or delaying the electricalsignals.

The present invention relates to improved methods and apparatus fortransferring a function from one record medium to a second recordmedium. More particularly. the present invention relates to improvedmethods and apparati for recording a previously recorded visiblefunction on a. second medium and modifying the original scale of thefunction to a predetermined scale. In a still more particular aspect,the present invention relates to improved methods and apparati fortransferring and changing a visibly recorded signal of a particularscale to a frequency modulated signal recorded at a predetermined scaleon magnetic tape.

This application is a division application of copending application63,750, now Patent No. 3,185,994 entitled, Log Transcribing and ScaleChanging Method and Apparatus, invented by John P. Woods, Edwin B.Neitzel and Tom Prickett, Jr., and owned by a common assignee.

The problem of transferring intelligence recorded in visible form on amedium to a second medium with or without scale changes is confronted inmany fields of endeavor. For instance, in various types of testing andmetering operations it is conventional to record the out put of theparticular test or metering equipment by oscillograph or other directreading recorders. To process or operate upon this data with modern-daycomputers, it is usually necessary to transfer the oscillograph recordsor other types of records to magnetic tape. Due to differences in recordtransport speeds, observing speeds, recording speeds, etc.. it issometimes necessary to change the scale of the originally recordedrecords to a new scale, requiring either linear or nonlinear scaleconversion.

The oil industry is similarly faced with the problem of transferringinformation previously recorded on film or paper to magnetic tape. Theproblem has become particularly acute with the advent of syntheticseismograms and the increased emphasis on correlation of various welllogs, seismic field records, or well logs and field records.

.In addition, the increased use of cross section plotters and seismiccomputers has also increased the importance of transferring previouslyrecorded records to magnetic tape since these devices usually operate onmagnetic records instead of film or visibly recorded records.

Prior to 1954,'most seismograms were recorded on film or on paper, andeven today, most well logs are recorded in that manner. As a result,there is an obvious need for an efiicient, accurate method oftransferring to magnetic tape the vast amount of data stored on welllogs and old seismograms.

The industrys growing reliance on automatic data processing mentionedabove, as Well as the growing' tendency to re-examine and correlate oldrecords and logs in an effort to find previously hidden producing sandsin explored areas, has also produced a need for a simple, inexpensive,and flexible means of changing the scale of an originally recordedsignal to a desired predetermined scale. This operation may requireeither a linear or nonlinear change. For instance, if a seismogram is tobe correlated with a well log, the scale of the seismogram or the logmust be changed since the physical length of the log is many times thephysical length of the seismogram. and since the log is plotted versusdepth and the seismogram is plotted versus time. If a log of adirectionally-drilled well is to be correlated with a verticallydrilledwell, the scale must be changed to the vertical depth. When a syntheticseismogram is to be constructed from a continuous velocity log or otherlog, the normal procedure is to change the scale of the continuousvelocity log to two-way travel time. Therefore, it is obvious from theexamples mentioned above that in most transcribing operations, it isnecessary to make appropriate scale changes when the originalinformation is being transferred to magnetic tape.

To the best of applicants knowledge, there is no method or apparatuspresently available that satisfactorily trans: fers a visibly recordedfunction to magnetic tape with the necessary scale changes. Photographicdevices are available for copying records and introducing scale changesby distorting the record. Various types of handoperated devices areavailable for following oscillographic recordings and changing same todirect reading visible records such as shown in United StatesPatent'2,866,596. Specially designed devices are available such as shownin United States Patent 2,638,671 for transforming a drilling time baselog with variable footage to a log showing constant footage plottedversus'variable time. However, all of these devices are unduly large,complicated, expensive, and/or slow. A simple, portable device capableof making a linear or nonlinear scale change of the desired amount.during the process of accurately transferring a visible recorded signalto magnetic tape is not presently available to industry.

Accordingly, it is the object of the present invention to provide animproved and versatile method and apparatus for transferring a functionrecorded on a medium to a second medium.

Another object of the present invention is to provide improved methodsand apparatus for transferring a function previously recorded on amedium to a second medium and producing any necessary predeterminedscale changes during the transfer operations.

Another object of the present invention is to provide improved methodsand apparatus for accurately transferring a function previously recordedas visible intelligence to a magnetic record.

Another object of the present invention is to provide improved methodsand apparatus for transferring a function previously recorded as visibleintelligence on a medium to a magnetic medium by utilizing a modulatedcarrier.

Another object of the present invention is to provide improved methodsand apparatus for transferring intelligence from a previously recordedwell log to a magnetic medium recorded in frequency modulated form.

Another object of the present invention is to provide improved methodsand apparatus for transferring a previously recorded function to asecond record medium and changingthe scale of at least the ordinate orabscissa of the function to a predetermined scale while the prerecordedfunction is being transferred to the second medium.

- Another object of the present invention is to provide improved methodsand apparatus for transferring a previously recorded function to asecond record medium and changing the scale of said function to apredetermined scale while said function is being recorded on said secondmedium.

Another object of the present invention is to provide improved methodsand apparatus for transferring a previously recorded function to asecond record medium and changing the scale of said function to apredetermined scale by variably advancing and/ or delaying the transfertime.

Another object of the present invention is to provide improved methodsand apparatus for transferring a function recorded on one medium to asecond medium and changing the scale of said function to a predeterminedscale by varying the speed of one record medium at predeterminedintervals.

Another object of the present invention is to provide. improved methodsand apparatus for transferring a previouslyrecorded function to a secondmedium and making a predetermined linear and/or nonlinear scale changeas the function isre-r'ecorded, on a second record medium.

Another object of the present invention is to provide a low frequencymodulator with an adjustable frequency range.

Another object of the present invention is to provide an improved 90phase shifting circuit that is designed to operate on inputs of varyingfrequencies.

These and other objects and advantages of the present invention will beapparent from the following detailed description. In order to simplifythis description, the invention will be described with reference to itsuse in transcribing well logs and seismograms onto magnetic tape.However, it is to be recognized that the invention can be used withother types of records such as will be described hereinafter.

Briefly, the over-all invention includes improved methods and apparatusfor scanning previously recorded visual information, translating theinformation into electrical signals, modulating a carrier with thesignals, making the required types of linear or nonlinear scale changeif this is necessary, and re-recording the information in modulated formon a magnetic tape or other desired medium. The invention makesavailable to the industry an inexpensive, simplified, flexible,portable, and highly accurate device for transforming previouslyrecorded information into the desired magnetic form for computer orrecorder operation.

Since the scale conversion method is unique and applicable to operationsother than Well log and seismic record transcription and since the noveland highly accurate transcribing method and apparatus may or may notinclude the scale conversion method, the two broad methods will bediscussed separately.

FIGURE 1 shows a record transcriber with two types of optionally usedscale correctors.

FIGURE 2 is a circuit diagram of an improved low frequency modulatorwith a variable frequency range.

FIGURE 3 is a schematic drawing of the preferred embodiment of the scalecorrector.

FIGURE 4 is a circuit diagram of an improved 90 phase shifting circuit.

FIGURE 5 is a diagram showing a transcribing device with an analog typescale cor'rector. FIGURE 6 is a drawing of a transcribing apparatus witha digital type scale Corrector.

FIGURE 7 is a diagrammatic representation of a digital type scalereduction.

4 Transcriber The transcriber shown in FIGURE 1 includes a movablefollower 1 connected through suitable means to potentiometer 3,modulator 5, and transducer head 7 positioned above record 9.Predetermined code marks 11 are positioned on chart 13 containing data15 and read by pickup 17. Modulator 19 is activated by relay 21 whenpickup 17 encounters mark 11. Transducer head 23 is driven by modulator19. Motor 25 drives chart 13 through the desired gear ratio in gear box27. A constant speed motor 29 drives chart 9 through a pulley andmetallic belt system 31. Optional scale correctors shown in dash blocks33 and 35 are not required in the transcribing operation, but are usedto illustrate two possible positions for scale correctors. In case scalecorrection is desired and corrector 33 is selected, motor 25 should be atype whose speed can be accurately controlled. The scale correctors arediscussed in detail hereinafter.

The purpose of the transcribing system is to transfer visibly recordedfunction 15 to a magnetic record 9 With the highest degree of fidelityand efficiency of operation.

Since the information carried in record 13 is contained in the variousamplitude variations or character changes shown in function 15, it isextremely important to transfer this intelligence to the magnetic recordwith a minimum of distortion and alteration. Although it is well knownthat FM recording provides maximum dynamic range and accuracy ofamplitude reproduction, in the past, other types of recording have beenused because it was thought PM was not feasible in the transcription ofrecords such as described herein. Applicants invention unexpectedlyovercome prior limitations to be described hereinafter and provides anovel method and equipment for using FM recording to transcribe oldrecorded information. It should be noted at this point that althoughfrequency modulation is most desired since it obtains maximum dynamicrange and maximum accuracy of amplitude reproduction, other types ofrecording can be used by applicants device.

By utilizing the novel approach of frequency modulation in this type ofoperation, various problems peculiar to PM recording must be overcome.Since in most cases the original record to 'be transcribed on tape willbe scanned at lower speeds than conventional playout speeds of magnetictape, it is necessary to utilize a novel low frequency modulator that issuitable for various scanning and transcribing speeds encountered. Therequirement for very constant low velocity rates of traverse are met bynovel use of variable gear ratios, stainless steel belts, and drivemotors, all of which will be described in more detail hereinafter. Themetallic steel belt referred to above is covered in copendingapplication 768,673, now Patent 3,126,626 owned by a common assignee. VThe most basic method of transferring information recorded in visibleanalog form on one medium to a second medium comprises the steps ofscanning the visible informatron, translating the originally recordedinformation into electrical signals, modulating a carrier with theelectrical signals, and re-recording the modulated carrier on a secondmedium.

a Let us now consider the preferred embodiment of the transcriber andthen consider in detail the operation thereof.

The preferred embodiment employs a hand-operated scanning device such asshown in FIGURE 1. By manually positioning pointer 1 over data 15 aschart 13 is driven by motor 25, potentiometer 3 is adjusted to operatemodulator 5. Since the preferred embodiment is being described,modulators 5 and 19 are FM modulators. These and other variations usedin the preferred embodirnent will be described in detail hereinafter.

FIGURE 2 shows two novel adjustable range, low frequency modulators thatmay be used in the preferred embodiment. The PM modulator shown in block5, FIG URE 2, is designed to record at a reduced scanning speed.

and contains an adjustable frequency range. Since the scanning operationis reduced in speed, the recording operation must also be reduced inspeed proportionately. For instance, assuming that normal magnetic tapeplayback speed is 7 /z inches of tape per second and the normal centerfrequency of the FM modulator is 2,500 cycles per second, then with zerosignal, 2,500 cycles are recorded on 7 /2 inches of tape. Therefore, itis clear that in the recording process the FM modulator must be made tooperate at frequencies compatible with the low speed of the record tapeto make the information readable at normal playout speeds.

To instrument this novel recording approach, the modulators in dashblocks 5 and 19 are utilized. FM modulator 5 includes a bank ofcapacitors 37 and a bank of capacitors 39, each of which is connected tomulticontact ganged switch 41. Banks 37 and 39 are connected to the gridof triodes 43 and 45. Rotary element 47 and 49 of gang switch 41 areconnected to the plates of triodes 43 and 45, respectively, and also tothe grid of triode 51 and the plate of triode 53.

' Triodes 43 and 45 together with capacitor banks 37 and 39 andassociated circuitry form a multivibrator portion of the modulatorcircuit. T riode 53 is an amplifier, and triode 51 serves as a cathodefollower to isolate the multivibrator from the amplifier 53. The PMmodulator 19 is similarly composed; i.e., capacitor banks 55 and 57connected together by gang switch 41 form with triodes 59 and 61 amultivibrator. Triode 63 serves as a cathode follower to isolate themultivibrator from the amplifier formed by triode 65.

Let us now consider transcribing a visible record to magnetic tapeutilizing the preferred embodiment of the novel transcribing method.

Briefly, the preferred method includes manually scanning visiblyrecorded information, translating the information into electricalsignals, frequency modulating a carrier 'with the signals at reducedrates commensurate with the manual scan rate, and recording themodulated carrier on a second medium at reduced rates.

This type of operation as well as others to be described may be utilizedfor varied operations, such as transcribing oscillograph records ormeter readings to tape, photographically recorded seismograms tomagnetic tape, electrically recorded or photographically recorded welllogs to tape or to a second visible medium in which other logs are alsorecorded for correlation purposes, etc. However, for ease ofexplanation, let us assume that it is desirable to transcribe aphotographically recorded seismogram to magnetic tape where no scalechange is necessary.'

Before actual transcription, certain preliminary steps must be taken.

Predetermined coordinating indicia are marked on the originalphotographic record. The position of the indicia is determined by thetype of final record to be produced and whether or not a scale change isto be made. In this case, no scale change is involved and the onlyrequirement is to transfer timing marks on the original record to thefinal record. Therefore, the desired number of timing marks on theoriginal record are marked by applying strips of burglar alarm tape, byusing conductive ink, or by other means to establish the predeterminedcode. This code will be recorded on the magnetic record as timing marks.

Drive ratios are selected in gear box 27 and pulley and belt system 31,FIGURE 1, to establish a desired basic scanning rate and appropriataerecording rate; i.e., the speeds of record 13 and tape 9. This ratio isdetermined by the type of scanning apparatus utilized. In this case,since record 13 will be scanned manually, the speed of record 13 and thecorresponding speed of tape 9 should be reduced approximately 500 timesso that the operator can properly track the data on record 13. Put inanother way, the speed of tape 9 is reduced approximately 500 times fromthe desired normal playout speed (i.e., 7 /2 inches per second, 10inches per second, etc.) to correspond to record 13s manual scan speed.

The proper range of modulator frequencies to correspond with the scaleddown recording speed of magnetic tape 9 is selected by using gangedswitch 41. That is, the selected modulator frequency range must recordthe same number of cycles per second at reduced record speed as will beplayed back at normal playout speed. It should be noted that the markermodulator 19 frequencies are also appropriately selected by gang switch41.

As a matter of interest, it should be noted at this time that system 31utilizes metallic belts and pulleys instead of gears to prevent gearnoise from interfering with the FM recording.

The various speed ratios and modulator ranges mentioned above can bereduced to chart form, and thus eliminate any need for computationsprior to a recording operation. This is true since there are onlyapproximately four basic well log scales used by service companies andonly a limited number of widely used magnetic record playback speeds(i.e., 7 /2 inches per second, 10 inches per second, etc.), andphotographic record speeds, Therefore, it is a simple matter toprecompute the various combinations of gear ratios and modulatorsettings and record in chart form for all recording eventualities.

The last preliminary step is to select the no signal condition orcarrier frequency of the FM modulator. This is done by positioningpointer 1, FIGURE 1, over 15 on log 13 so it is centered in the middleof the maximum amplitude excursion.

With the preliminary steps over, actual transcription can be initiated.Seismic photographic record 13 is slowly driven under marker 1 by motor25 operating through gear box 27 to drum 33. As data 15 moves underpointer 1, control knob 67 is manually adjusted to maintain pointer 1 ondata 15. When pointer 1 is moved, potentiometer 3 is varied, producing avoltage which is used as a bias and applied to the grids ofmultivibrator tubes 43 and 45, FIGURE 2. The preselected" capacitor 5chosen by positioning gang switch 41 controls the frequency range of themodulators 5 and 19. The amount of bias voltage applied to the modulatortubes 43 and 45 controls the output frequency of multivibrator 5. Theoutput of the multivibrator 5 is sent through cathode follower 51,amplifier 53 and to transducer head 7 shown in FIGURE 1, where it isrecorded on tape 9.

Simultaneously with the transciption of data 15 shown in FIGURE 1, codemarks 11 approach pickup 17. Prior to the passage of a code mark underpickup 17, frequency modulator 19 shown in FIGURE 2 produces a constantfrequency output as selected by the setting of gang switch 41. As a codemarker 11 passes under contact 17 shown in FIGURE 1, the metallic stripshorts out the contact and temporarily changes the DC bias applied tothe grids of multivibrator tubes 59 and 61, FIGURE 2. The resulting biasproduces'an FM signal which passes through cathode follower 63,amplifier 65, and to transducer head 23, FIG- URE 1, where it isrecorded as a timing signal on tape 9.

The novel method of transcription described above can be carried out inmany and varied different ways. For instance, the record to betransferred can be automatically scanned or semi-automatically scannedas desired. If it is desirable to automatically scan the data, aphotoelectric cell such as shown in FIGURE 5 or other well-knownautomatic scanners can be utilized to read the data. If it is desirableto operate semi-automatically, a photoelectric scanner can be utilizedin combination with a manual tracking means so that as the scanner readsthe intersection of two crossing data lines, the manual operator cantake over and maintain the data reader on the proper information. In anycase, the output from such reading devices can be utilized tomodulate acarrier which is recorded on magnetic tape or the like. As pointed outheretofore, if FM modulation is not desired, amplitude modulation orother suitable modulation can be practiced.

Scale correction The basic scale correcting method can be practiced byusing a variable speed drive and controller therefor, or by using avariable advance and delay and controller therefor.

The purpose of the scale changing system is to provide a simplified yetaccurate means to adjust the scale of originally recorded information toa predetermined scale on magnetic tape or other recording medium. Anadditional purpose is to provide a flexible scale changing syst em sothat av linear-to-linear, a linear-to-nonlinear, or anonlinear-to-linear scale change may be made during the process oftranscription.

. By utilizing the novel approach of operating on the information or theoriginal or transcription record at predetermined intervals, anextremely accurate and flexible system of scale changing is produced.

The general method of scale conversion includes the steps of placing apredetermined code on the medium bearing an originally recorded functionafter the function has been recorded on the medium, simultaneouslyscanning the code and the function, re-recording the scanned functionand modifying the scale of the function as dic tated by thepredetermined code.

The subject method is capable of two basic variations in practice. Thatis, the scale change can be produced by varying the speed of one recordat predetermined intervals by corrector 33, FIGURE 1, or the scalechange can be produced by operating on the scanned function by advancingand delaying it predetermined amounts by corrector 35. Either correctorcan be used with the basic transcriber shown in FIGURE 1 and discussedheretofore; however, it should be noted that either corrector or anyvariation thereof can also be used with other types of transcribingsystems.

Let us now describe the preferred method of scale change and thepreferred apparatus for performing same.

FIGURE 1 shows the over-all combination transcriberscale corrector.Either scale corrector 33 or 35 can be used with the transcriber. Scalecorrector 33 is the preferred corrector and is arranged to vary the scanspeed of record 13 at predetermined intervals marked by code 11. Duringeach interval, the speed will be varied a predetermined amount so thatthe new record will have the code marks separated by equal intervals ofrecord. It should be also understood at this time that the rate ofrecord 9 can be varied instead of record 13; however, if FM recording isused, the modulator would have to be compensated for the speedvariations.

FIGURE 3 shows in detail the preferred embodiment of scale corrector 33in FIGURE 1. Block 69, FIGURE 3, discloses an automatic means forcontrolling the speed of drive motor 25, FIGURE 1. The control meanscontains a bank of potentiometers 71, a bank of trim capacitors 73, aplurality of multicontact ganged switches 75 operated by relays 77, anda series of diodes 79 connected with the switches in such a way as toform a stepping matrix. The operation of same will be explained in moredetail hereinafter. Block 69 is connected to oscillator 81 which in turnis connected to phase shift network 83. This network is connected topower amplifier 85 and power amplifier 87, respectively, and they inturn are connected to respective windings 89 and 91 in synchronous motor93. Power supply 95 is connected to filter 97, which in turn isconnected to oscillator 81, phase shifter 83, one-shot multivibrator 99,and control means 69. Reset switch 101 is connected to phase shifter 83,control 69, and manual step switch 103. As will be apparent after thedetailed description,'reset switch 101 causes matrix 69 to shift to thepreoperation position whereby relay 77 is activated.

Step switch 103 causes the next higher numbered relay to be operated.

Before considering the operation of the preferred embodiment, refer toFIGURE 4 which shows in detail a novel degree phase shifting circuitdesigned for operation in block 83, FIGURE 3. The problem of providingvoltages 90 degrees out of phase to 90 degree windings on a synchronousmotor is a relatively simple operation when the input frequencies remainconstant. However, when the input frequency to a phase shifting circuitis continually varied, the problem of maintaining a 90 degree phaseshift becomes very diflicult. The novel, simplified, and flexible phaseshifting circuit shown in FIGURE 4 is adapted to meet this problem. Tothe best of applicants knowledge, no presently used phase shiftingcircuit is capable of operating with such dependability and simplicityof circuit design.

The novel circuit as shown in FIGURE 4 includes drive flip flop 105 anddriven flip flops 107 and 109. Flip flop 105 includes input circuit 111and transistors 113 and 115. Transistor 113 is connected throughdifferentiating circuit (capacitor 117 and resistor 119) and triggertransistor 121 to flip flop 107. Transistor is connected throughdifferentiating circuit (capacitor 123 and resistor 125) and triggertransistor 127 to flip flop 109. As will be shown in the detaileddescription of the operation of FIG- URE 3, the phase shifting circuitshown in FIGURE 4 is capable of maintaining a 90 degree phase shiftbetween its output voltages regardless of the input voltage frequencyvariation. Therefore, regardless of the output frequencies programmed by69, synchronous motor 93 receives the required two voltages that are 90degrees out of phase.

Let us now consider the detailed operation of the preferred method andapparatus for producing a scale change. Since the preferred embodimentof the scale changing operation involves changing the scan rate of theoriginal record at predetermined intervals, the novel operation may bedescribed as follows.

A method of changing the scale of a function prerecorded on an originalmedium to a predetermined scale on a second medium while the prerecordedfunction is being transferred to the second medium comprising the stepsof placing a predetermined speed change code on the medium bearing theprerecorded function after the function has been recorded on the medium,concurrently scanning the function and the speed code and producingoutputs therefrom, and re-recorcling the function on the second mediumat a new scale determined by the speed code output.

Let us assume for purposes of illustration that it is desirable toproduce a synthetic seismogram from a particular type well log. Assumingthe log is from a vertically drilled well, the scale change involved ischanging the linear depth scale of the well log to a linear travel time(two-way) for the seismogram. The step of filtering the log to produceseismic frequencies, even though necessary 1n producing a syntheticseismogram, is not important in the scale changing operations and willnot be discussed.

To better understand the over-all operation, it is necessary to discusspreliminary operations designed to set up an apparatus that is capableof practicing the novel method of scale changing. The preliminaryoperations can be broken down into those required to establish a desiredspeed change code on the original log and the preliminary operationsnecessary to set up a machine for transferring the original log to themagnetic record.

The preliminary operations are as follows:

Determining the position of the speed change code (in th s case, two-waytravel time marks). The purpose of this operation is to break theoriginal log or record into a predetermined number of sections so thatby varying the scan speed (or delay) at the start of each of thesepredetermined sections, the scanned information is recorded on aun1formly moving magnetic tape producing a predetermined scale change.Unless a nonlinear scale is to be recorded, the speed change code marksare recorded in equally spaced positions along the magnetic tape.

The determination of the position of the speed code can me accomplishedmathematically in various ways. The most simple method is to utilize theaverage seismic velocities (furnished with each log of interest) anddetermine the depths of one tenth second intervals of twoway traveltime.

Of course, any suitable equal interval can be used. The predeterminedintervals are marked on the log or record by using strips of burglaralarm tape, conductive ink, or other suitable markings.

Since the preferred embodiment of the device capable of practicing thepreferred method of scale change utilizes an automatic speed changingcontrol 69, FIGURE 3, it is necessary to set in potentiometers 71, 71,etc., each of which will be sequentially connected by voltage developedfrom a speed code marker 11, the resistance necessary to produce afrequency change to drive the synchronous motor 93 at the next newpredetermined speed. Knowing the inherent capacitive and resistivecombination in oscillator 81, it is basic to determine the resistancesettings required to produce the desired frequency changes required todrive synchronous motor 93 at its new predetermined speeds. The numberof potentiometer settings. to be made depends upon the number of codemarks placed on the record. Of course, the number of potentiometers 71is not important to the inventive concept; and if more settings arerequired than the number of potentiometers available, speed changingcontrol 75 can be reprogrammed as the device switches through theoriginal settings.

1 The preliminary steps of selecting the correct scanning and drivingratios, modulator range, and proper carrier frequency were disclosed inthe discussion of the transcribing method. Since for purposes ofillustration that transcribing method is used to record the function inthis scale changing method, no further'elaboration is necessary.

With the preliminary operations accomplished, log 13 bearing data 15,FIGURE 1, is moved under pointer 1'. Pointer 1 is continuallyrepositioned by control knob 67, which in turn varies bias potentiometer3. The varying bias produced controls the output frequency of modulator'5. The PM signal is recorded by head 7 on tape 9. Simultaneously withrecording the data, the initially selected speed-ofmotor 25 shown inFIGURE 3 as synchronous motor 93 drives log 13 at the selected speed.Asthe first speed code- 11 passes under contact 17, the code shorts outthe contact, actuating .one-shot multivibrator 99, FIGURE 3, sending apulse through contact 129, diode 79' to actuate relay 77' and closeganged switch 75'. Thus, each succeeding pulse from multivibrator 99closes the next succeeding ganged switch in 69 in the same manner. Withthe activation of ganged switch 81', the resistance setting inpotentiometer 71 and the capacitance in trimmer capacitor 73 areincluded in the circuit of oscillator 81. This new combination 'ofresistance and capacitance changes the oscillator output frequency of 81to a new predetermined value shown as frequency ;f and wave form 131 inFIGURE 4. Phase shift circuit 83, FIGURE 3, shown in detail in FIGURE 4receives oscillator output 131 at input 111. Flip flop 105 is actuatedby pulse trian 131 to produce square wave trains .133 and 135. Both 133and 135 occur at frequency 1; however, they are 180 degrees out ofphase. The respective dilferen-I tiating circuits produce waves 133' and135, which are used to actuate trigger'transistors 121 and 127, which inturn trigger flip flops 107 and 109. Output wave 133" from 107 is now 90degrees out of phase with output 135", and the frequency of the outputwaves are f/2 or one-half the input frequency. Therefore, regardless ofthe oscillator or input frequency I, outputs 133" and 135" are 90degrees out of phase as they are fed to their respective poweramplifiers and 87 in FIGURE 3.

It is evident from the explanation above that each pulse created byspeed code 11, FIGURE 1, sequentially pulses control 69 in such a mannerthat a new predetermined frequency is fed to the synchronous motor,which in turn drives chart 13 at the new predetermined speed. Thereforechart 13 is variably driven to introduce the desired scale change as thedata is recorded on the tape driven at a constant speed.

A simplified variation to the method described above involves manualoperation of the scanner and modulator as well as manual selection ofthe input frequencies to the synchronous motor. Although this method ofoperation is slower than the method discussed above, it has proven quitesuccessful over an extended period of usage. The instrumentation of thismethod includes a manual tracking and modulating system as disclosed inFIGURE 1 with a different speed control system.

In operation, pickup switch 17 is connected to a sig nal lamp. Thepassage of a marker 11 under '17 flashes the lamp, at which time anoperator punches a new precomputed frequency into the keyboard of aconventional signal generator connected to a synchronous motor drivingchart 13.

Let us now briefly consider another embodiment of the basic scale.changing method which operates on the signal by advancing or delaying itinstead of vary: ing the speed of one record. Refer now to the basictranscriber and scale corrector 35 shown in FIGURE 1. Corrector 35 ispositioned to operate on the modulated signal from the scanned data.This system of scale change utilizes digital or analog operations toenter the desired scale change.

I For instance, if an analog-type system is desired to make theappropriate scale changes, a variable delay such as a magnetic delayline is controlled by a function generator or other device to operate onthe data read from chart 13 before it is recorded on record 9. FIGURE 5shows one type of scale corrector capable of performing the analogmethod of scale correction. Scale corrector 35 shown'in FIGURE 1 isincluded in dash block 35 on FIGURE 6. This particular embodiment'includes function generator 137, which includes a curve 139 mounted on adrum 141, a curve follower 143, andservo 145. Magnetic delay drum 147includes a magnetic head v149 arcuately movable around delay drum 141 byservo 145. Curve 139 is a plot of a correction function (delay oradvanceversus time) necess'ary to accommodate scanned data 15 to thedesired scale change on record 9. For complete details of an analogdevice suitable for entering such a delay, see copending application749,190, now Patent No. 3,156,892, owned by a common assignee.

It should be understood that if data 15 is scanned manually, thepreviously discussed appropriate reduction in recording speed andmodulator speed (if FM modulation is used) is necessary. If reducedspeeds are used, it should also be understood that an appropriateincrease in delay time is also necessary. If data 15 is electronicallyscanned, then no scale-down is required and the recording and delaysystemcan be driven at a normal speed. Assuming that chart 13 is scannedby an electronic eye 151 in a manner known'to those skilled in the art,the information so scanned is utilized to modulate modulator 5 which isrecorded on delay drum 141. Predetermined advance and delay curve 139read out by curve follower 1 43 operates servo 145, which in turn causesreadout head 149 to enter the appropriate head movements to stretch orcompress the scanned information so the final signal recorded bymagnetic head 7 on record 9 is recorded to the desired predeterminedscale. In other words, curve 139 causes pickup head 149 to advance ordelay the signal recorded on drum 147 amounts necessary to make thedesired scale change.

FIGURE 6 shows a digital delay type scale corrector used with atranscribing apparatus such as disclosed in FIGURE 1. The scalecorrector shown in dash block 35 includes delay tape 153, seriallyconnected input circuit 155, oscillator 157, wave shaping circuit 159,and counter 161, which controls magnetic delay line 163.

In order to better understand how this device performs the scalechanging operation, FIGURE 7 presents in a highly simplified fashion alog 13 and a magnetic tape 9. Code marks 11 have been placed on log 13to indicate ,4 second two-way travel time intervals determined in amanner explained in the discussion of the speed changemethod above. Theunequal distances between the various code marks 11 on chart 13 indicatethat a nonlinear scale correction must be made if the data recorded on13 is to be transcribed on magnetic tape 9 at equal A two-way traveltime intervals.

If the scale-change and the final transcription operation are to be madein one operation, the method can be as follows. The speed ratios in 27and 31, FIGURE 6, are selected in such a manner that the largest two-waytravel time x on record 13 is scaled down mechanically to the desireddistance x on tape 9 by virtue of the speed ratios selected. Theremaining increments of data 15 between code marks 11 on log 13 must nowbe delayed through corrector 35 appropriate amounts to equal the firstincrement x on tape 9. To produce the appropriate delays for eachincrement, a program tape or chart 153 is produced as disclosed incopending application, 790,631, owned by a common assignee. This programtape is produced to contain the required number of delay pulses betweeneach code 11 to cause that increment of data 15, when played back fromchart 13, to be delayed sufliciently to equal increment x when recordedon tape 9. That is, the total delay (required to stretch a particularincrement of data 15 to equal x) is divided by the width of a singledelay pulse to give the number of delay pulses required for a particularincrement of data. These delay pulses are placed on the program tape inthe manner described in application 790,63 1, now Patent No. 3,328,754,to produce the predetermined scale change.

In operation, chart 13 and tape 9 are driven at the proper speeds tochange distance x to x during a given time. Data 15 is read out by 151,or other suitable means, and fed through modulator 5 and delay drum 163onto tape 9. The above-described program or delay tape 153 operates insynchronism with the movement of chart 13 and delay pulses from thistape are fed through input circuit 155, oscillator 157, wave shapingcircuit 159 to counter 161. Each pulse from the delay program actuatescounter 161 and adds a minute incremental delay to the.

data scanned from tape 13 by 151. The delays added to the.

increment of data between each code 11 causes it to equal distance xwhen recorded on tape 9.

If desired, the digital delay type correction may be varied to includethe following method. Speed reduction ratios between 27 and 31 aredetermined as described above to cause distance x on 13 to equaldistance x on tape 9. Log 13 is then played out and recorded on tape 9in a linear fashion as prescribed by the gear reduction ratio. It isobvious from observing FIGURE 8 that the smaller incremental distancesbetween code marks 11 are recorded on tape 9 as increments less than x.To adjust these distances to equal x, it is necessary to play back tape9 and enter the proper delays by the digital (or analog) operation andre-record the adjusted data on a second tape.

Although the methods and apparatus have been illustrated for operationon seismic and logging data, it is obvious that the invention is just asappropriate for other operations requiring the transcription to magneticrecord and/or appropriate scale changes. Therefore, it is to be observedthat although specific embodiments of the instant invention have beenillustrated and described herein, various modifications andsubstitutions may be made which will be obvious to those skilled in theart, without departing from the scope of the present invention which islimited only by the appended claims.

We claim:

1. A scale corrector for controlling the playback speed of a record inaccordance with a predetermined speed code comprising (a) a one-shotmultivibrator activated by said code,

(b) speed control means connected to said multivibrator including aplurality each of potentiometers, trim capacitors, multicontact gangedswitches, and relays,

(c) an oscillator connected to said speed control means,

(d) a 90-degree phase shifting circuit connected to said multivibratorand to said oscillator, and

(e) a synchronous motor connected to said phase shifting circuit fordriving said record.

2. A scale corrector as forth in claim 1 where at least one poweramplifier is connected between the phase shifting circuit and thesynchronous motor.

3. An analog scale corrector for use when a function is being transposedfrom a first record to a second record comprising (a) a delay drum onwhich said function is temporarily recorded,

(b) a transducer means arcuately movable about said delay drum forreading said function,

(c) a function generator for producing a predetermined scale correctionfunction, and

(d) a servo for moving said transducer means according to said scalecorrection function.

4. A digital scale corrector for use when a function is being transposedfrom a first record to a second record comprising (a) a delay drum onwhich said function is temporarily stored,

(b) a plurality of transducer means fixedly located at positions aboutsaid delay drum for reading said function,

(c) an input circuit for reading a preprogrammed delay tape,

(d) an oscillator connected to and controlled by said input circuit,

(e) a pulse counter connected to said oscillator, and

(f) switching means connected to said counter for activating saidtransducer means'according to instructions on said delay tape.

References Cited UNITED STATES PATENTS 2,881,416 4/1959 Hosken 340-3472,923,871 2/1960 Cohen 318171 2,975,399 3/1961 Burns 340l5 3,157,87411/1964 Altar 343-5 3,283,133 11/1966 Field 235-481 DARYL W. COOK,Acting Primary Examiner.

MAYNARD R. WILBUR, Examiner.

J. H. WALLACE, Assistant Examiner,

1. A SCALE CORRECTOR FOR CONTROLLING THE PLAYBACK SPEED OF A RECORD INACCORDANCE WITH A PREDETERMINED SPEED CODE COMPRISING (A) A ONE-SHOTMULTIVIBRATOR ACTIVATED BY SAID CODE, (B) SPEED CONTROL MEANS CONNECTEDTO SAID MULTIVIBRATOR INCLUDING A PLURALITY EACH OF POTENTIOMETERS, TRIMCAPACITORS, MULTICONTACT GANGED SWITCHES, AND RELAYS, (C) AN OSCILLATORCONNECTED TO SAID SPEED CONTROL MEANS, (D) A 90-DEGREE PHASE SHIFTINGCIRCUIT CONNECTED TO SAID MULTIVIBRATOR AND TO SAID OSCILLATOR, AND (E)A SYNCHRONOUS MOTOR CONNECTED TO SAID PHASE SHIFTING CIRCUIT FOR DRIVINGSAID RECORD.